Iwannis studied and became a monk at the Monastery of Eusebuna. He was later ordained metropolitan of Hauran and was elected and consecrated as patriarch in 740. When the Caliph Marwan II, visited Hauran, the patriarch Iwannis presented him with fifty camels laden with gifts, the caliph honoured him and gave him a decree of authorisation.[1]

After his death in 754, the Caliph al-Mansur appointed two successors without being elected by the Holy Synod and are considered "intruders" by the Syriac Orthodox Church.